The incidence rate of skin cancer has substantially increased in the last decade of the 20th century. It is appreciated that over 1.3 million new skin cancers are diagnosed annually, which is increasing at a rate of about 5% per year. Increased exposure to the sun without skin protection and a decreased ozone layer are regarded as the main causes of this increase—a problem estimated to be costing over 1 billion Euros in annual medical treatment expenses. Over 80% of skin cancers occur in the head and neck regions with 50% occurring in patients over 60 years of age. It is expected that a portion of the senior population will double in year 2025 compared to the present demographics. Because of the growing incidence of skin cancer and increasing share of the senior population in the overall demographics, much focus has been placed on cancer treatments and cancer treatment logistics.
Non-proliferative cancers, which are defined by substantially superficial lesions, may be treated in different ways. In one example, non-proliferative cancers may be treated surgically. Surgery, however, may have certain drawbacks, such as, for example, long waiting lists, complications related to post-treatment care, and risk of infection. Alternatively, patients may undergo irradiation using electrons of soft X-rays. Irradiation may have an advantage of being non-invasive and of a short duration (a treatment session may be as short as 2 to 4 minutes). It will be appreciated that usually the integral treatments using radiotherapeutic techniques may require a number of sessions.
Recently, the use of a mobile and portable X-ray unit has been suggested, which may be used inside a hospital radiotherapy department. An embodiment of such a unit is described in US 2007/0076851. Existing X-ray units include an X-ray source and a filtering device having a plurality of filters rotatably arranged with respect to a focal point of the X-ray tube for changing filtering characteristics on demand. The plurality of filters are arranged in a filtering device, which is transversely arranged with respect to a longitudinal axis of the X-ray tube. These units, while effective, may have certain drawbacks. For example, X-ray beam characteristics may be affected by the internal geometry of the X-ray tube, leading to, for example, a broadened penumbra of the X-ray beam.